A 62-year-old male with a history of Wegener's granulomatosis and immunosuppressive therapy presented with chronic olecranon bursitis. A black velvety mould with brown septate hyphae and tapered annellides was isolated from a left elbow bursa aspirate and was identified as an Exophiala species. Internal transcribed sequence rRNA sequencing showed the isolate to be identical to Exophiala oligosperma. The patient was successfully treated with aspiration and intrabursal amphotericin B.Exophiala species are dematiaceous, or dark-pigmented, dimorphic hyphomycetes that are found at low density in relatively extreme microniches, such as oligotrophic waters or preservative-treated wood. The species most commonly involved in human infection are Exophiala jeanselmei complex members, Exophiala spinifera, and Exophiala dermatitidis, with other species at low frequency (4, 6, 28). They are generally associated with phaeohyphomycosis, which encompasses a heterogeneous group of infections that are histologically defined by the presence of yeast-like or hyphal forms of the fungus in superficial subcutaneous locations or disseminated systemic disease. The increased detection of Exophiala species as agents of human disease is also believed to be related to the increased number of immunocompromised hosts (2,10,24,26,27). We report an unusual case of olecranon bursitis attributed to the newly recognized species Exophiala oligosperma (7).(Presented at the 102nd General Meeting of the American Society for Microbiology, 21 May 2002 [abstract F-80] .)Case report. A 62-year-old male with Wegener's granulomatosis presented to the University of Iowa rheumatology clinic in July 2001 with chronic painless left elbow swelling. The patient was known to rest his elbows on a sink while irrigating his sinuses twice daily for chronic sinusitis. The elbow was not warm or erythematous. Raised scabbed areas were observed on the skin over the olecranon process that had been present for at least 8 months. The patient exhibited no other signs of infection, and his white blood cell count was within normal limits. The patient's vasculitis had been treated with prednisone, 20 mg daily, which was tapered to 5 mg every other day, and cyclophosphamide, 100 mg daily, for several months. The olecranon bursa was aspirated, and 15 ml of fluid was removed.No organisms were seen on Gram or calcofluor white stains. Fungal cultures on potato dextrose agar initially grew yeastlike colonies that developed into an olivaceous black velvety mould with aerial hyphae and a black reverse (Fig. 1). Microscopically, the hyphae were septate and pale brown. Conidia were formed in small clusters both from intercalary loci along undifferentiated hyphae and from tapered annellidic conidiogenous cells (Fig. 2), features characteristic of Exophiala species. Two subsequent aspirations from the left olecranon bursa ϳ1 month apart (3 and 7 weeks after the initial aspiration) also grew Exophiala species.The isolate was submitted for species identification to the Fungus Testing Laborator...